Yet another Mars architecture

RobertDyck · 2015-01-22 21:16:50

SpaceNut wrote:

As for the SRB resonance with fuel burn think changing the harmonic by creating a fret ( think Guitar) inside the chamber for the pitch to change to as the fuel burns. Had a sliding sleeve inside that moves up or down the walls of the chamber to make the change...

Excellent idea. It's basically a pipe organ. I was worried changing the harmonic would require change of gross length, so the 5th segment would have to be custom. And shorter means less thrust. Or change to a cone, again changing the harmonic, but also reduced propellant. A slotted metal pipe of a pipe organ can be tuned by moving a cover up or down along the slot, effectively changing the length of the pipe. But for a rocket, you don't want a side slot to release pressure. From Wikipedia:

An open metal pipe usually has a sliding collar ("tuning slide") at the top of the pipe that can be moved to change the pitch.

So add a tuning slide to the SRB. Rather than a complete obstruction, as some pipe organs, as you suggest use a sleeve. It would be tuned during development/testing, then fixed. Could you use a cylinder open on both inner and outer surfaces? The point is to reflect the sonic wave, not obstruct exhaust flow. Perhaps burn channels cut (moulded) in the rubber propellant between the sleeve and outer casing.

kbd512 · 2015-01-22 21:26:39

SpaceNut wrote:

The risk assessment for a rocket flies even in the face of the shuttle as after columbia was destroyed astronauts were ready to fly the Hubble rescue mission even without a chance of a safe haven if it had recieved damage.
As for the SRB resonance with fuel burn think changing the harmonic by creating a fret ( think Guitar) inside the chamber for the pitch to change to as the fuel burns. Had a sliding sleeve inside that moves up or down the walls of the chamber to make the change...

This is a good example of why America needs more than one launch system and more than one spacecraft ready to go at all times.

HST cost the taxpayers billions, more than the cost of an orbiter and STS launch combined. That's too much money to throw away because some rinky dink part failed, however spectacularly.

The TPS should be inspected on any spacecraft, irrespective of whether or not it was hit by anything, before reentry. Columbia was not an example of how fragile or dangerous STS was, but rather how arrogant the engineers who were running operations could be. If the TPS of a spacecraft is damaged, a small unmanned rocket with tools and parts should have been ready to go to fix it on orbit.

Whereupon Dragon is man rated, NASA should have a Dragon/Falcon 9 as a back up to any Orion mission. If we're sticking with the requirement for triple redundancy in manned space flight systems, perhaps a second Dragon should be ready to go at ISS. If that hundred billion dollar space station buys us anything, it really ought to include the ability to fix minor problems with damaged spacecraft.

GW Johnson · 2015-01-23 09:31:24

Re: thrust oscillations in SLS SRB's. It is my second-hand understanding that the offending mode in the 5-segment motors is a quarter-wave fundamental longitudinal instability that didn't show up in the shuttle 4-segment SRB's. Such resonances tend to be fairly sharply defined by susceptible geometries.

Maybe some sort of baffle might help. It does not necessarily have to be variable geometry; some fixed baffles have quieted oscillations in tactical missile size motors before. This is a solution decades old. It won't be a reusable item, though. The environment in an aluminized solid is quite harsh. Fast moving very hot solids of soot and aluminum oxide droplets are quite erosive, and the gas temperature is pretty near 6000 F. The radiation heat transfer from the solids to the structures is also super extreme.

One should bear in mind that the organ-pipe mode is not the only mode in which solid motors "sing". At least in the smaller sizes, radial and circumferential modes at far higher frequencies are the most common "offenders". You distinguish them partly on the basis of their frequencies, after having analyzed the geometry and conditions for what all the possible modes could be. That kind of analysis is pretty common in the small motor houses, not very common among the big motor boys, sorry to say.

Re: safety / redundancy practices vs program management -- The truly arrogant ones regarding the Columbia disaster were the managers, the engineers were simply ignorant (they could not believe that foam could break carbon-carbon, a 500 mph impact being outside ordinary human experience). The same management arrogance was true for Challenger, with the engineers not having ignorance for an excuse.

Depends on which engineers, though: Thiokol engineers told them not to fly, the NASA engineers know a whole lot less about solids.

But in both fatal accidents, it was managers who ignored technical advice and did what they wanted to do. In the case of Challenger, the scapegoat was to be the engineers, and the bad management was to be covered up. That got exposed during the hearings.

GW

Last edited by GW Johnson (2015-01-23 09:43:12)

kbd512 · 2015-01-23 12:53:08

If you have a couple billion dollars worth of flight hardware riding on your prudent decision making, suspend all disbelief. Don't take a wild guess at whether or not something could be a problem. If you know something struck your spacecraft because you have a video of it, no further evidence should be necessary to warrant an inspection. There's just no excuse for that.

For the love of all that's holy, if the manufacturer of a product tells you there's a problem with it then pay attention. If you don't understand, ask questions. Some part of that has to be incorporated into Critical Thinking 101, a class that's apparently not taken often enough or not taught widely enough.

GW Johnson · 2015-01-23 17:19:45

kbd512:

What you say is perfectly true. The problem is that ignoring outside advice is part and parcel of the "not invented here" arrogant attitude that US government labs and agencies are so infamous for (for well over 7 decades now), out in the contracting industry. The public is relatively unaware of this, but needs to be made aware. However, any contractor who tells the truth in public gets no more business. And that's the plain truth of it. It an evil, but it is quite real.

GW
"been there and seen it on the inside many, many, many times"

SpaceNut · 2015-04-24 20:09:06

Here is another one with thumbs up from Buzz Aldrin impressed by Purdue’s plan for Mars

A human colony on Mars could be just 25 years and several steps away.
Fifty-one Purdue University students in a senior spacecraft design class this year compiled a 1,000-plus page report detailing the resources and actions necessary to colonize Mars by 2040. “The class works as a single team to achieve a specified space mission goal, which in this past I have dictated as the customer,” professor James Longuski said. “This time was a little different. ... In this particular project, the students were given a unique opportunity to work with Buzz Aldrin and his concepts for colonizing Mars.”

https://engineering.purdue.edu/AAE/Acad … Report.pdf

“We should do everything we can before we make a landing,” Aldrin said, “and when we make one, we make a commitment to permanence.”
Timeline to Mars
2022-2028 — establish several bases on the Moon
2028-2029 — begin building hardware necessary for Martian colony
2030s — pre-deliver equipment to Phobos and Mars
2031-2033 — launch cycler vehicles
2037-2039 — establish base on Phobos
2039-2040 — colonize Mars
2040-2044 — establish second Martian colony
By the numbers 92 total launches necessary before 2040
87 additional launches between 2040-2044
6,586 tons of mass launched into space before 2040
6,656 more tons launched between 2040-2043

RobS · 2015-04-25 07:13:29

This is a pretty impressive report! It's packed with useful information, too; delta-vs, masses, types of equipment to take to Mars, ways to solve problems like radiation, etc. Interesting to note that they propose raising only 40% of the food on Mars and importing 60%, using aeroponics (misting roots with nutrient-rich water rather than using Martian soil), and using LED lighting powered by a nuclear reactor rather than sunlight.

louis · 2015-04-25 08:40:44

Thanks SpaceNut - a fantastic report. Isn't it shaming for NASA what a bunch of students can do - presumably at v. low cost - in terms of mission planning?

Anyway, I will certainly look into this proposal. It does seem to be replete with fascinating detail and well thought out.

That said, I believe we could do it more cheaply (and quickly) than that, with far fewer launches (on my reckoning we could get a six person colony up and running on under 25 launches). Pre-landing of supplies and facilities is the key to a minimalist mission.

SpaceNut wrote:

Here is another one with thumbs up from Buzz Aldrin impressed by Purdue’s plan for Mars
A human colony on Mars could be just 25 years and several steps away.
Fifty-one Purdue University students in a senior spacecraft design class this year compiled a 1,000-plus page report detailing the resources and actions necessary to colonize Mars by 2040. “The class works as a single team to achieve a specified space mission goal, which in this past I have dictated as the customer,” professor James Longuski said. “This time was a little different. ... In this particular project, the students were given a unique opportunity to work with Buzz Aldrin and his concepts for colonizing Mars.”
https://engineering.purdue.edu/AAE/Acad … Report.pdf
“We should do everything we can before we make a landing,” Aldrin said, “and when we make one, we make a commitment to permanence.”
Timeline to Mars
2022-2028 — establish several bases on the Moon
2028-2029 — begin building hardware necessary for Martian colony
2030s — pre-deliver equipment to Phobos and Mars
2031-2033 — launch cycler vehicles
2037-2039 — establish base on Phobos
2039-2040 — colonize Mars
2040-2044 — establish second Martian colony
By the numbers 92 total launches necessary before 2040
87 additional launches between 2040-2044
6,586 tons of mass launched into space before 2040
6,656 more tons launched between 2040-2043

kbd512 · 2015-04-25 09:58:23

Dream big, but be prepared to be confronted with reality. We lack fundamental technologies required for human habitation. There's no budget to do what the kids from Purdue want to do, either, but that's a minor technical detail.

* CL-ECLSS
* Active Radiation Shielding
* SEP tug
* Interplanetary Transit Vehicle
* HIAD and ADEPT

All other elements of any deep space mission are a question of what you want to do when you get to wherever you want to go. The five enabling technologies listed above are hard requirements. If ARM was taken seriously, we'd have CL-ECLSS, a SEP tug, and Interplanetary Transit Vehicle. We may get a proof-of-concept SEP tug and one deep space test of Orion from ARM.

We're going to need a real HLLV if we want to lift that much tonnage. If SLS was a 150t capable vehicle by 2022, that works out to roughly 2.5 launches per year between 2022 and 2040. The current budget would support no more than 1.5 launches per year. I seriously doubt that SLS will be much more than a 105t capable vehicle in its most capable configuration. At 115t-125t, SLS is pretty near to the practical limit of what that vehicle's design would be capable of without a complete redesign to add a 5th RS-25 (confirmed by ATK) or liquid boosters (something that there's no infrastructure or even room on the pad to support).

If F9H could be developed into a 100t class vehicle with a significantly larger payload shroud while not simultaneously dramatically increasing launch costs, the launch schedule would be supportable from a budget perspective. That would mean a redesign of F9H, though.

The flight schedule alone is a bit unrealistic with existing rockets. Ten years from now, who knows? Anything's possible.

Start really small. That means small capsules, small ITV's, and small landers. We can concern ourselves with colonization and whatnot after we get there. We have to get there first. I think we need to stop pushing the master colonization plans until we get there. That doesn't mean we stop thinking big, but in the near term we must focus on all the incremental technology advancements and test objectives required to realize the dream.

RobS · 2015-04-25 12:27:53

The Purdue report is over a thousand pages and is downloadable, so it is well worth downloading so you can find it again. It has a lot of gems in it.

Regarding Falcon Heavy, I don't think we can assume that the first version that flies this summer will be the final version. The Falcon-9 v 1.1 is being upgraded now and the new upgrade will have 10-15% more thrust in the first and second stages. If you add that to the Heavy, that will raise its payload. It would be very tempting, also, to give the Heavy a bigger second stage, and it probably would not cost that much more to do so (same engine, bigger tanks). I bet the Heavy can be tweaked to put 60 tonnes into LEO, maybe even more.

And there's the so-called MCT or Mars Colonial Transporter. Its design keeps changing; Musk says he'll announce his first draft architecture to go to Mars some time this year. They've been talking about landing 100 tonnes on Mars, which would require launching about 450 tonnes into LEO. That would be a BIG rocket. One also wonders whether, as a way to develop the MCT, Musk might not want to develop a small methane-fueled second stage to launch with the Falcon Heavy, in order to gain experience with the system. If so, the Falcon Heavy could get even more capable.

GW Johnson · 2015-04-25 16:30:52

Don't forget the time-phasing effect. There is a point in any project where you must "freeze" the design, or you will never fly. That has to be frozen with stuff that is fully ready-to-apply, or else, once again, you will never fly.

I think you can assume safely that there will be available in the next few years versions of Atlas-5 and Delta-4 that can carry up to but not much past 20 metric tons to LEO. I think you can assume there will be versions of Falcon-9 that can carry 13 tons to LEO. I think you can assume that there will be versions of Falcon-Heavy that will carry 50-53 tons to LEO.

I am extremely unconfident that you can assume anything about SLS over the initial 70 tons to LEO, if indeed that ever really comes true at all. If SLS turns out like X-30 and X-33 did, nothing usable will ever fly on that program. Could be better, could be worse. I just dunno. So I DO NOT COUNT ON IT. Neither should you.

You need to fix your mission designs to use the rockets we know "for sure" we will have. Then if we actually turn out "better", things just get easier and cheaper. If they don't turn out better, then we can still do it.

It's just basic common sense, tempered by history.

GW

kbd512 · 2015-04-25 17:50:56

GW,

It would seem that someone in Congress forgot about, perhaps ignored, or more likely never read Part Deux of Akin's Law #39 since none of those morons are aerospace engineers.

I think we've blown too much money on SLS to throw everything away. There's no explanation that passes muster as to why it wasn't originally designed as a 125t to 150t rocket, though.

Why do so many mission architectures put forth by big name universities, astronauts, and scientists rely on hardware that only exists on paper? Shouldn't these people know better than to rely on paper hardware? More money from heaven nonsense?

SpaceNut · 2015-04-25 18:37:58

Kbd512, I would say that we have near readiness on three on these Items

* CL-ECLSS, * Active Radiation Shielding, * SEP tug, * Interplanetary Transit Vehicle, * HIAD and ADEPT

and that GW Johnson
is right in that

There is a point in any project where you must "freeze" the design, or you will never fly. That has to be frozen with stuff that is fully ready-to-apply, or else, once again, you will never fly.

So when is that "lock in date" ; if we keep saying its sometime in the future that we are going to Mars then we can just keep dreaming of the far off future items that we do not have currently that makes a mission a snap.

Robs you are quite right that

The Purdue report is over a thousand pages and is downloadable, so it is well worth downloading so you can find it again. It has a lot of gems in it.

and I hope to comb through every page learning as I read what it will take to start a mission with what we have.

That said with the phase out of Delta IV heavy and Atlas V haulting due to Russian engines with a combined ULA giving a make over in the next generation vehicle, it leaves just Space X Falcon 9 as the only game in town to launch just 20 T's to orbit to make a current vehicle design with.

RobertDyck · 2015-04-25 18:50:05

Saturn V was originally designed on paper to lift 130t to LEO, or 45t to TLI. SLS is claimed to be able to lift 130t to LEO. Coincidence? No way! Saturn V as built was able to lift 118t to LEO, or 47t to TLI. Optimization for the Moon. Design for SLS is already going through adjustments, expect changes. However, proposed adjustments make me fear nothing above 70t will get built.

RobS · 2015-04-25 20:04:43

I think it will be very hard to build any version of SLS that can throw over 70 t to LEO, unless Congress gets substantially more dysfunctional and irrational than it already is. By the time SLS flies, Falcon Heavy will have been flying 2 years or so and will be about 1/5 as expensive WITHOUT reuse. The ULA plans for Vulcan will have rendered the planning for SLS obsolete, too. The French are already scrambling to build a cheaper rocket and the Russians are looking at the problem, too. Furthermore, by then it will be clear what Musk plans to build next. I suspect it would be easy for him to upgrade Falcon Heavy so that it gets a lot closer to 70 t. SLS is so expensive, we can't afford to build anything for it to launch. NASA didn't want to build SLS; Congress mandated it instead. More and more people will see the handwriting on the wall, I think.

But the Purdue-Aldrin people pretty much had to include it and include Falcon Heavy. The alternative would have been to propose a new rocket as part of their plans.

I am more intrigued by the cycler than I thought I would be. Maybe it's a half decent idea after all.

RobertDyck · 2015-04-25 20:38:56

I'm still frustrated. SLS is the shuttle ET, SME, SRB, and upper stage uses J-2X which is an upgrade of the J-2 used by Saturn V. J-2 was upgraded to J-2S in 1965-1972. So why is it taking so long, so expensive?

kbd512 · 2015-04-25 21:22:07

SpaceNut,

I disagree about near-readiness, unless that's defined as ten years down the road. It should be taken for granted that anything NASA does these days will have been tested to perfection before they ever stake the lives of humans on the readiness of a particular technology or system. The whole "going to Mars with the hardware you have" idea is quaint, but deep space is a completely unforgiving environment.

I don't think deep space testing is going to produce any heretofore unknown issues with ISS-derived mission hardware, but we're still farting around in LEO more than four decades after we did send men into deep space. The worst part is that we already have the hardware for deep space transit.

At this point, I see no reason why we couldn't attempt a manned Mars flyby with existing hardware or hardware scheduled to be flown in the next few years.

* ISS laboratory module outfitted with avionics, RCS, ECLSS, PE water tank for SPE shielding, and five berthing ports
* 4 BEAM modules attached to the lab-hab to hold consumables (to provide slightly more pressurized volume than a MPLM, split the consumables between four modules instead of one, and not require development of a "utility tunnel")
* Assembly at ISS (finally using ISS for what it was originally intended for)
* Use Dragon for crew transfer (it's going to be man rated before Orion is)
* Chemical kick stage for orbital transfer (no advanced propulsion required)

This mission would require 2-3 F9H flights. The cost for the mission hardware would likely be equivalent to the cost for a SLS rocket. Total mission cost would likely be double or triple what a SLS rocket costs. In other words, mission costs for the flyby are within the realm of NASA's current manned space flight budget and not something far out in fantasy land, as the Purdue mission architecture is.

That'd be a darn good test of the various habitability elements required to support future deep space missions. If there's funding available for more advanced inflatable habitat modules, Skylab II style modules, and/or artificial gravity modules, fine. If not, we'd have a vehicle capable of ferrying humans around the inner solar system that we've actually tested in deep space. The SEP and EDL tech would still be required for achieving orbit and landing, but we'd be a heck of a lot closer to manned Mars exploration than we are today.

kbd512 · 2015-04-25 21:43:44

RobertDyck wrote:

I'm still frustrated. SLS is the shuttle ET, SME, SRB, and upper stage uses J-2X which is an upgrade of the J-2 used by Saturn V. J-2 was upgraded to J-2S in 1965-1972. So why is it taking so long, so expensive?

Rob,

What don't you get about this?

SLS is not STS hardware. It's an all-new, untested rocket.

The avionics are all-new.

They have to develop a new payload shroud.

The upper stage program was never completed.

They've completely replaced the control unit for the RS-25. May as well be a new untested engine.

The SRB's are 5 segment, not 4 segment, and they constructed slightly differently. May as well be a new untested SRM.

The mobile launch platform had to be upgraded because it wasn't designed for the crushing weight of SLS.

The existing pad facilities had to be redesigned and upgraded because the exhaust from the RS-25's is not diverted in the same manner and the facilities were literally crumbling after three decades of continuous use.

The VAB integration hardware had to be refurbished, replaced, and/or redesigned to accommodate a very different vehicle from STS.

In every way that matters, SLS is a completely new and untested rocket that required numerous infrastructure changes to support operations.

Retiring Saturn V was a mistake of SLS proportions. That's what happens when you let stupid people, like the overwhelming majority of American politicians, decide which projects live and die. That's our system of governance, as dumb as it is, and we have to live with it or start a revolution to change it. We'd be having a conversation about colonizing Mars or going to Jupiter right now if NASA was appropriately funded and permitted to use its resources as it saw fit. That's not the world we live in.

RobertDyck · 2015-04-25 23:49:12

Wikipedia wrote:

Between 1960 and 1962, the Marshall Space Flight Center (MSFC) designed a series of Saturn rockets that could be used for various Earth orbit or lunar missions. ... On January 10, 1962, NASA announced plans to build the C-5

Apollo 4, vehicle serial number SA-501, was the first unmanned all-up test flight: November 9, 1967.

Ares V was developed as part of the Constellation program, started by signing the NASA Authorization Act of 2005, signed on December 30, 2005. Obama cancelled it on October 11, 2010. SLS was revived by the Senate in September 2011. And yes, I do included development time and money spent for Ares V. That's 4 years and 10 months for Ares V, and 3 years and 6 months for SLS. It only took 5 years and 10 months for Saturn V, including developing the F-1 and J-2 engines from scratch. Including the time and money for Ares V, we should have seen an unmanned all-up test flight by now.

GW Johnson · 2015-04-26 14:17:48

RobertDyck:

There's a conversation going on in interplanetary transportation, about this very topic from your last post just above.

There is a very good reason the same contractors can no longer do what they once were able to do.

GW

louis · 2015-04-26 14:38:08

I think you're overengineering.

We are there on all fronts now I would say, given development time. Any leaps required are as nothing compared with what was achieved in the five years between Apollo going from design to a lunar-capable system.

The solution to many of the supposedly "insurmountable" problems is pre-landing of supplies a landing zone.

Entry is not a problem - it is clear to me that the Space X cantilevered design will work. We just need a minimal descent/ascent vehicle. Once people get to the surface they can then transfer within 3 days to a full functioning hab that has been pre-landed.

We don't need anything bigger than 50 tonne loads as we can assemble the transfer vehicle in LEO from multiple parts.

The health effects of a long term mission can be tested in a lunar orbiting and lunar landing test run.

kbd512 wrote:

Dream big, but be prepared to be confronted with reality. We lack fundamental technologies required for human habitation. There's no budget to do what the kids from Purdue want to do, either, but that's a minor technical detail.
* CL-ECLSS
* Active Radiation Shielding
* SEP tug
* Interplanetary Transit Vehicle
* HIAD and ADEPT
All other elements of any deep space mission are a question of what you want to do when you get to wherever you want to go. The five enabling technologies listed above are hard requirements. If ARM was taken seriously, we'd have CL-ECLSS, a SEP tug, and Interplanetary Transit Vehicle. We may get a proof-of-concept SEP tug and one deep space test of Orion from ARM.
We're going to need a real HLLV if we want to lift that much tonnage. If SLS was a 150t capable vehicle by 2022, that works out to roughly 2.5 launches per year between 2022 and 2040. The current budget would support no more than 1.5 launches per year. I seriously doubt that SLS will be much more than a 105t capable vehicle in its most capable configuration. At 115t-125t, SLS is pretty near to the practical limit of what that vehicle's design would be capable of without a complete redesign to add a 5th RS-25 (confirmed by ATK) or liquid boosters (something that there's no infrastructure or even room on the pad to support).
If F9H could be developed into a 100t class vehicle with a significantly larger payload shroud while not simultaneously dramatically increasing launch costs, the launch schedule would be supportable from a budget perspective. That would mean a redesign of F9H, though.
The flight schedule alone is a bit unrealistic with existing rockets. Ten years from now, who knows? Anything's possible.
Start really small. That means small capsules, small ITV's, and small landers. We can concern ourselves with colonization and whatnot after we get there. We have to get there first. I think we need to stop pushing the master colonization plans until we get there. That doesn't mean we stop thinking big, but in the near term we must focus on all the incremental technology advancements and test objectives required to realize the dream.

kbd512 · 2015-04-26 15:44:01

louis wrote:

I think you're overengineering.
We are there on all fronts now I would say, given development time. Any leaps required are as nothing compared with what was achieved in the five years between Apollo going from design to a lunar-capable system.

Your first statement there pretty much sums up the problem. If only development time and funding that is not available due to the congressionally mandated Orion and SLS projects was made available, a manned Mars mission would be achievable. The statement "We think we have the solutions to mission requirements for a manned Mars mission" and "We have flight rated hardware sitting over there waiting to be launched to Mars" are two entirely different statements. We can't make the latter statement because we don't have a single piece of hardware ready for a manned Mars mission. More than four decades after the stated goal was publicized by NASA, we still have no flight rated hardware for that purpose.

We could continue to pump money into the manned space program for another two decades to give NASA's corporate partners "something to do". We won't have anything to show for it, but we could do that. Alternatively, we could issue an ultimatum with a timeline attached to it. Either NASA figures out how to get humans to Mars in ten years or less with the existing budget or we pull the funding for the manned space program. My first six years of employment were spent working for Uncle Sam. Sometimes you have to light a fire if you want something accomplished.

louis wrote:

The solution to many of the supposedly "insurmountable" problems is pre-landing of supplies a landing zone.

Caching supplies on the surface doesn't solve any problems unless you're close enough to reach the cache. Being highly mobile on the surface of Mars lowers landing tonnage requirements, not caching supplies. You can always litter landing areas with supplies if you want to, but that increases tonnage requirements.

louis wrote:

Entry is not a problem - it is clear to me that the Space X cantilevered design will work. We just need a minimal descent/ascent vehicle. Once people get to the surface they can then transfer within 3 days to a full functioning hab that has been pre-landed.

I agree with need to have minimalist descent/ascent solutions for humans, but what does the SpaceX "cantilevered design" have to do with that?

louis wrote:

We don't need anything bigger than 50 tonne loads as we can assemble the transfer vehicle in LEO from multiple parts.

Having true heavy lift vehicles reduces the number of assembly operations required, but it's not a show stopper.

louis wrote:

The health effects of a long term mission can be tested in a lunar orbiting and lunar landing test run.

We already know what the long term health effects of microgravity and radiation exposure are, but for whatever reasons NASA has devoted no funding to implementation of artificial gravity and there's no serious funding devoted to active radiation shielding.

SpaceNut · 2015-04-26 18:50:32

I have not had the chance to run the numbers but this is what Loius is refering to:

louis wrote:

Entry is not a problem - it is clear to me that the Space X cantilevered design will work. We just need a minimal descent/ascent vehicle. Once people get to the surface they can then transfer within 3 days to a full functioning hab that has been pre-landed.
kbd512 wrote:
I agree with need to have minimalist descent/ascent solutions for humans, but what does the SpaceX "cantilevered design" have to do with that?

http://en.wikipedia.org/wiki/SpaceX_reu … nt_program

The reusable launch system technology is under development for the first stages of the Falcon family of rockets. It is particularly well-suited to the Falcon Heavy where the two outer cores separate from the rocket earlier in the flight, and are therefore moving more slowly at stage separation. If the technology is used on a reusable Falcon 9 rocket, the first-stage separation would occur at a velocity of approximately 2.0 km/s (6,500 km/h; 4,100 mph; Mach 6) rather than the 3.4 km/s (11,000 km/h; 7,000 mph; Mach 10) for an expendable Falcon 9, to provide the residual fuel necessary for the deceleration and turnaround maneuver and the controlled descent and landing. The reusable technology will also be extended to both the first and upper stages of the future launch vehicle for the Mars Colonial Transporter.

If you label launch after refueling on Mars and look at booster burn back as the descent to Mars we have what would be a powered landing with no parachutes or heat shield as a developing method of how to solve the mars landing.

Finally found the altitude of seperation....

http://www.technologyreview.com/news/52 … -to-earth/

A camera on the second stage of the rocket captured live video of the nine SpaceX-built Merlin engines firing on the first stage of the rocket, with the plume of flame and smoke gradually expanding as the air around the vehicle thinned. At about 50 miles in altitude, and traveling at about 10 times the speed of sound some 35 miles off the Florida coast, the first-stage engines cut off as planned. As the first stage dropped away, the single Merlin engine in the second stage fired to propel the Dragon craft the rest of the way into orbit. Another camera view showed the Dragon moving away from the second stage into space with the Earth as a backdrop.

louis · 2015-04-27 05:00:12

I've never thought NASA was going to get us there. It will be a Space X led mission (maybe with a NASA badge on it to save face).

The key thing about pre-landing of supplies is that you can reduce the tonnage that has to be landed with the descent vehicle and the individual pre-landing missions can be quite low tonnage (with payloads in the 1-5 tonne range). I think we could land within supplies with a well defined zone and then tow them (robotically) to the central landing area. With transponders pre-landed on the surface the descent vehicle can land accurately.

You say we already know what the long term health effects of microgravity and radiation exposure are. True and we know most people recover well - but we don't know how well people might recover on the moon with lead weight suits designed to replicate 1G. We should test that - as it would be a good guide to how they will recover from zero G on Mars.
I think the radiation issue is being overplayed. We can have emergency shelters in the transhab and we can look at ways of provide better cover on the Mars surface.

kbd512 wrote:

louis wrote:
I think you're overengineering.
We are there on all fronts now I would say, given development time. Any leaps required are as nothing compared with what was achieved in the five years between Apollo going from design to a lunar-capable system.
Your first statement there pretty much sums up the problem. If only development time and funding that is not available due to the congressionally mandated Orion and SLS projects was made available, a manned Mars mission would be achievable. The statement "We think we have the solutions to mission requirements for a manned Mars mission" and "We have flight rated hardware sitting over there waiting to be launched to Mars" are two entirely different statements. We can't make the latter statement because we don't have a single piece of hardware ready for a manned Mars mission. More than four decades after the stated goal was publicized by NASA, we still have no flight rated hardware for that purpose.
We could continue to pump money into the manned space program for another two decades to give NASA's corporate partners "something to do". We won't have anything to show for it, but we could do that. Alternatively, we could issue an ultimatum with a timeline attached to it. Either NASA figures out how to get humans to Mars in ten years or less with the existing budget or we pull the funding for the manned space program. My first six years of employment were spent working for Uncle Sam. Sometimes you have to light a fire if you want something accomplished.
louis wrote:
The solution to many of the supposedly "insurmountable" problems is pre-landing of supplies a landing zone.
Caching supplies on the surface doesn't solve any problems unless you're close enough to reach the cache. Being highly mobile on the surface of Mars lowers landing tonnage requirements, not caching supplies. You can always litter landing areas with supplies if you want to, but that increases tonnage requirements.
louis wrote:
Entry is not a problem - it is clear to me that the Space X cantilevered design will work. We just need a minimal descent/ascent vehicle. Once people get to the surface they can then transfer within 3 days to a full functioning hab that has been pre-landed.
I agree with need to have minimalist descent/ascent solutions for humans, but what does the SpaceX "cantilevered design" have to do with that?
louis wrote:
We don't need anything bigger than 50 tonne loads as we can assemble the transfer vehicle in LEO from multiple parts.
Having true heavy lift vehicles reduces the number of assembly operations required, but it's not a show stopper.
louis wrote:
The health effects of a long term mission can be tested in a lunar orbiting and lunar landing test run.
We already know what the long term health effects of microgravity and radiation exposure are, but for whatever reasons NASA has devoted no funding to implementation of artificial gravity and there's no serious funding devoted to active radiation shielding.

louis · 2015-04-27 14:50:33

The reusable rocket will certainly reduce the costs of the Mars Mission but I was referring to the "Red Dragon" proposal for a lander:

http://www.space.com/24984-spacex-mars- … ragon.html

SpaceNut wrote:

I have not had the chance to run the numbers but this is what Loius is refering to:
louis wrote:
Entry is not a problem - it is clear to me that the Space X cantilevered design will work. We just need a minimal descent/ascent vehicle. Once people get to the surface they can then transfer within 3 days to a full functioning hab that has been pre-landed.
kbd512 wrote:
I agree with need to have minimalist descent/ascent solutions for humans, but what does the SpaceX "cantilevered design" have to do with that?

http://en.wikipedia.org/wiki/SpaceX_reu … nt_program
The reusable launch system technology is under development for the first stages of the Falcon family of rockets. It is particularly well-suited to the Falcon Heavy where the two outer cores separate from the rocket earlier in the flight, and are therefore moving more slowly at stage separation. If the technology is used on a reusable Falcon 9 rocket, the first-stage separation would occur at a velocity of approximately 2.0 km/s (6,500 km/h; 4,100 mph; Mach 6) rather than the 3.4 km/s (11,000 km/h; 7,000 mph; Mach 10) for an expendable Falcon 9, to provide the residual fuel necessary for the deceleration and turnaround maneuver and the controlled descent and landing. The reusable technology will also be extended to both the first and upper stages of the future launch vehicle for the Mars Colonial Transporter.
http://upload.wikimedia.org/wikipedia/c … raphic.jpg
If you label launch after refueling on Mars and look at booster burn back as the descent to Mars we have what would be a powered landing with no parachutes or heat shield as a developing method of how to solve the mars landing.
Finally found the altitude of seperation....
http://www.technologyreview.com/news/52 … -to-earth/
A camera on the second stage of the rocket captured live video of the nine SpaceX-built Merlin engines firing on the first stage of the rocket, with the plume of flame and smoke gradually expanding as the air around the vehicle thinned. At about 50 miles in altitude, and traveling at about 10 times the speed of sound some 35 miles off the Florida coast, the first-stage engines cut off as planned. As the first stage dropped away, the single Merlin engine in the second stage fired to propel the Dragon craft the rest of the way into orbit. Another camera view showed the Dragon moving away from the second stage into space with the Earth as a backdrop.

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